Influence of Protein Standardization by Ultrafiltration on the Viscosity, Color, and Sensory Properties of Skim and 1% Milk

Abstract

Permeate and retentate (concentration factor ca. 2x) from UF of skim milk were combined, and cream was added to produce skim milk (0.1% fat) and 1% milk with a range of true protein contents (1.0 to 4.8%) within each fat level. A panel that had been trained for descriptive sensory analysis evaluated the appearance, aroma, flavor, and textural attributes of milks. Relative viscosity and Hunter color values for whiteness (L value), greenness to redness (a value), and blueness to yellowness (b value) increased when either protein or fat was increased. The rate of change of L, a, and b values as protein content changed was greater for skim milk than for 1% milk and was greater as protein contents decreased. Sensory scores for several descriptors of appearance, texture, and flavor had a stronger positive correlation with objective measurements of whiteness than with objective measurements of viscosity. Thus, the judgment of panelists about milk texture and flavor in milks that differed in protein content was influenced more by appearance than by viscosity. As the protein content of skim and 1% milk was increased from 2.9 to 4.8% true protein, the sensory properties of the milks were made more like those of higher fat milk, particularly those of skim milk, mainly because of whiter appearance. Panelists perceived changes in the sensory characteristics of both skim and 1% fat milk when the true protein content was increased by 0.9%, the smallest increase that was studied in the experiment.

The effect of free Ca2+ on the heat stability and other characteristics of low-heat skim milk powder

“…The measurement of the colour was used by others for establishing a relationship between a chemical characteristic and the physical properties of milk (Philippe et al, 2003;Quinones et al, 1997).…”

Characterizing milk aftertaste: The effects of salivation rate, PROP taster status, or small changes in acidity, fat, or sucrose on acceptability of milk to milk dislikers

“…Altering the fat content (Frost et al, 2001;Phillips et al, 1995), protein content (Quinones et al, 1997, Quinones, Barbano, & Phillips, 1998, levels of defects such as oxidation (Lawless & Claassen, 1993), and other components of milk Phillips et al, 1995) have been shown to change the sensory properties of the milk, but no researchers have concentrated strictly on how the aftertaste of milk is altered when making such changes. Therefore, a fourth objective of this research was to examine several changes in milk for their ability to lessen the intensity and/or persistence of any of the aftertaste attributes.…”

“…Claassen and Lawless (1992) defined mouthcoating as Ôthe amount of residue remaining in the mouth, especially on the cheeks and tongue, after swallowing or expectorating.Õ They defined mouthdrying as Ôthe dryness, tightness, or roughness felt in the mouth after swallowing or expectoratingÕ, and irritation was defined as Ôthe sensation in the back of the throat associated with residue remaining after swallowing or expectoratingÕ. A number of researchers Phillips, McGiff, Barbano, & Lawless, 1995;Quinones, Barbano, & Phillips, 1997, 1998 have included the aftertaste terms ÔastringentÕ, Ôoverall residual flavorÕ, and Ôresidual mouthcoatingÕ in their descriptive analysis vocabularies for milk. Frost, Dijksterhuis, and Martens (2001) used the term Ôresidual mouth fillÕ, defined as the Ôdegree of residual mouthcoating after expectoration of the sampleÕ.…”

Feelings as a basis for discrimination: Comparison of a modified authenticity test with the same–different test for slightly different types of milk

“…how milk sensory properties are affected by CLA (conjugated linoleic acid) fortification (Campbell, Drake, & Larick, 2003), lipolysis and proteolysis caused by storage (Wiking, Frøst, Larsen, & Nielsen, 2002), different levels of fat in milk (Frøst, Dijksterhuis, & Martens, 2001), and different levels of protein and fat (Quinones, Barbano, & Phillips, 1997 …”